Rotary piston and cooling means therefor



Feb. 7, 1967 YASUO TATSUTOMI 3,302,524

ROTARY PISTON AND COOLING MEANS THEREFOR 4 Sheets-Sheet 1 Filed June 22,1965 Fig.

Yasuo Tafsufami l NV E NTOR l ,I m

l4 l4 ATTORNEYS Feb. 7, 1967 YASUO TATSUTOMI ROTARY PISTON AND COOLINGMEANS THEREFOR 4 Sheets-Sheet 2 Filed June 22, 1965 Yasua TafsufamiINVENTORS BY J ATTOR N EYS 1967 YASUO TATSUTOMI 3,302,624

ROTARY PISTON AND COOLING MEANS THEREFOR Filed June 22, 1965 4Sheets-Sheet 5 2 2/ Fig. 7

29; Y Yasuo Tarsufomi a INVENTOR Mum/1 9c 0 28 ATTORNEYS 1967 YASUOTATSUTOMI 3,302,624

ROTARY PISTON AND COOLING MEANS THEREFOR Filed June 22, 1965 4Sheets-Sheet 4 Yasua Tarsufami ATTORNEYS United States Patent 3,3h2,d2i

Fatenterl Feb. 7, 1967 fine 3,302,624 R-(BTARY PHSTGN AND CBGLHNG MEANSTHEREFGR Yasuo Tatsutomi, Hiroshima-hen, Japan, assignor to Toyo KogyoCompany Limited, Hiroshima-ken, Japan Filed June 22, 1965, Ser. No.465,845

Claims priority, application .lapan, June 24, 1964, 39/35,"?09; July 21,1964, 39/ 21,611, 39/41,612, 39/ 11,613

7 Ciaims. (Cl. 123-8) The present invention relates to a rotary pistoninternal combustion engine and particularly to a cooling means forcooling the rotary piston thereof by the circulation of the coolingfluid within the piston of the engine.

Generally a rotary piston internal combustion engine comprises apolygonally shaped rotary piston eccentrically rotating within acombustion chamber defined by an annular center casing having atrochoidal shaped internal peripheral wall and end walls on the oppositeends of the annular casing, so as to thereby effect intake, compressionof combustible gas for firing within the combustion chamber andexhausting of the product of combustion therefrom. The power istransmitted through a crankshaft which extends through the center of thecombustion chamber and the end walls and has the rotary pistoneccentrically rotatably mounted on a crank pin eccentrically mounted onthe crankshaft. Cooling of the rotary piston during the operation of theabove described engine is carried out by supplying cooling fluid tochambers provided within the piston. However, due to the above mentionedspecific structure of the engine, exhausting of the fluid from thechambers in the piston must be in the lateral direction though the fluidis under the effect of the centrifugal force due to the rotation of thepiston. This causes an impediment to the circulation of the fluid andcauses a deterioration of the cooling effect because of the stagnationof the fluid. In view of this problem it has been suggested to provideadditional equipment within the fluid chamber in the piston tofacilitate exhausting of the fluid, but such a device has provedimpractical for the engine because the structure of the device isrelatively complicated and causes an increase in the cost of the engine.

An object of the present invention is to provide a simple structural andeihcient functional cooling device for the rotary piston of the enginejust described.

Another object of the invention is to provide a cooling device for thepiston of the above described engine which performs cooling bycirculation of cooling fluid by the action of alternate acceleration anddeceleration of the rotational velocity of the rotary piston.

Other and further objects of the invention will become apparent from thefollowing specification and claims, taken together with the accompanyingdrawings, in which:

FIG. 1 is a longitudinal sectional view of a rotary piston internalcombustion engine according to the present invention;

FIG. 2 is an elevation view, partly in section, of a rotary pistonshowing the cooling fluid guides provided therein;

FIG. 3 is a fragmentary sectional view taken on the line 3--3 of FIG. 2;

FIGS. 4 and 5 are elevation views, partly in section, of the rotarypiston similar to FIG. 2 wit]: modified forms of cooling fluid guides;

FIG. 6 is a fragmentary sectional view taken on the line 66 of FIG. 4;

FIG. 7 is a longitudinal sectional view similar to FIG. 1 of a rotarypiston engine with a modified cooling fluid circulation system;

FIG. 8 is an elevation view, partly in section, of the rotary piston ofFIG. 7;

FIG. 9 is a fragmentary sectional view taken on the line 99 of FIG. 8;

FIGS. 10 and 11 are elevation views, partly in section, of a rotarypiston similar to FIG. 8 with modified forms of the cooling fluidguides; and

FIG. 12 is a fragmentary sectional view taken on the line 12-12 of FIG.10.

Referring first to F168. 1, 2 and 3, a combustion chamber a is definedwithin an annular casing 1 having an internal peripheral wall which istrochoid-shaped and two end walls 2 and 2 at the opposite ends thereof.Extending through the center of the combustion chamber a is a crankshaft3. Essentrically rotatable positions within the crankshaft bushings 4fixed in the end walls 2 and 2. integral with the crankshaft 3 is acrank pin 5 which is eccentrically positioned with respect to the axisof the crankshaft 3. Essentrically rotatable positions within thechamber a is a triangular rotary piston 6 having an axial bearing boss 7concentrically positioned therein. Within said bearing boss 7 the crankpin 5 of the crankshaft 3 is rotatably inserted in a bushing 8 fixed inthe boss 7 so as to thereby support the rotary piston eccentrically androtatably. Extending radially outwardly from the bearing boss 7 arevane-shaped cooling fluid guides 9 which are disposed at an angle to aradial plane through the axis of rotation and at properly spacedintervals around the outer peripheral face of the bearing boss 7.Radially outwardly spaced from the boss 7 and surrounding the radiallyouter ends of the guides 9 is an annular peripheral wall it? having aradially inwardly extending brim 11 at the opposite ends thereof forclosing the fluid chambers 12 which are radially and obliquely laterallydivided by the guides 9 extending between the boss 7 and the wall 16,leaving and radially inward corner openings 13 and 14 in the chambers 12at the opposite ends thereof. It will be noted that the corner openings13 at one end of the chambers are offset backwardly relative to therotational direction from the openings 14 at other end thereof, and thecooling fluid is supplied from said backwardly offset openings 13 andexhausted from the forwardly olfset openings 14 by the effect of thedeceleration of the rotational velocity of the piston as explainedlater. The bearing boss 7, fluid guides 9, peripheral wall 10 and brim11 will preferably being formed integrally with the rotary piston 6.

Encircled by the brim 11 and o ening in the opposite direction at theopposite ends of the piston are circular apertures 15 and 16 into whichthe corner openings 13 and 14 open laterally so that the fluid chambers12 are connected with the apertures 15 and 16. Provided within the endwalls 2 and 2' are fluid holes 17 and 13 respectively connected to theapertures 15 and 16 and adapted to supply and exhaust cooling fluid toand from the fluid chambers as described later. Fixed in the circularaperture 15 is an internal gear 19 concentric with the piston and whichmeshes with an external gear 24) which is concentric with the crankshaft3 and fixed to the end wall 2 so as to thereby effect the regulation ofthe rotation of the piston. Numeral 21 designates seals between apexesof the piston and the internal peripheral face of the annular casing 1and numeral 22 designates seals between each end face of the piston andthe internal face of the end walls 2 and 2.

The engine is operated in the conventional manner by firing thecompressed gas compressed within the chamber a by the effect of theeccentric rotation of the triangular piston 6. Intake of combustible gasand exhausting of the products of combustion is carried out by means ofconventional intake and exhaust ports (not shown). As the circulation ofthe cooling fluid within chambers 12 is performed by the effect of thedeceleration of the rotational velocity of the piston and theinclination of the guides 9 on the boss 7, as described later, thesupply of cooling fluid must come from the side towards which the fluidguides 9 are backwardly inclined with respect to the rotation directionof the piston and, through corner openings likewise backwardly offset.Therefore, according to the embodiment shown in FIG. 1, cooling fluid issupplied from a source of fluid (not shown) by conventional meansthrough the hole 17 and received through the aperture 15, into which thefluid is drawn by the centrifugal force due to the rotation of therotary piston and urged to flow into the chambers 12 through corneropenings 13. With the rotation of the rotary piston 6 the crank pinbeing eccentric to the crankshaft 3 and with the crank pin 5 rotatablypositioned within the hearing boss 7, the piston 6 rotates eccentricallyand transmission of the rotation movement of the rotary piston istransmitted through the crankshaft 3.

Due to the eccentric rotation of the triangular piston and thetrochoidal internal face of the casing 1 along which the apexes of thepiston move, the rotational velocity of each apex of the piston issubject to alternate acceleration and deceleration dependent on thecurvature of the trochoidal face and the radial distance from theeccentric rotation center of the piston and because the eccentricrotation of the piston is effected by the internal gear 19 which mesheswith the external gear and rotates eccentrically around said gear 20,acceleration and deceleration of the rotational velocity of the apexestakes place at spaced time intervals in rotational order at all of theapexes according to the rotation of the piston. With above describedrotation movement of the piston the centrifugal force due to suchrotation is also locally increased and decreased in rotational order. Itwill be noted therefore, that the action of the above describedrotational velocity of the piston and the centrifugal force act on thecooling fluid within each chamber 12 to cause a vortical current in therotational direction of the piston as shown by the arrows in FIG. 2.This vortical current acts to prevent the stagnation of the fluid andcauses the fluid to flow into every corner of the chambers. Assuming nowthat the peripheral velocity of the piston decelerates at some localportions of the piston during the rotation thereof, the cooling fluidunder the effect of the inertia within the chamber 12 is compelled toflow along the guides 9 due to the inclination thereof as shown in FIG.3 and is exhausted laterally into the circular aperture 16 through thecorner openings 14-. Such specific local portions at which the rotationvelocity decelerates shift along the periphery of the piston during therotation of the piston, and exhausting of the fluid from all of thechambers 12 is performed in rotational order during the rotation of thepiston. The exhausted fluid in the aperture 16 is conveyed away throughthe fluid hole 18 in the end wall 2'.

According to the present invention the circulation of the cooling fluidthrough the rotary piston is automatically carried out by the effect ofthe eccentric rotation of the rotary piston and, since the flow of thefluid is along the inclined guides 9, circulation of the fluid isfacilitated and promotes the cooling of the rotor without stagnation ofthe fluid. Leakage of the fluid between the opposite ends of the rotarypiston and the internal face of the end walls 2 and 2 is blocked by theseals 24.

FIGS. 4 and 6 show a modified form of the piston 6a which is similarlymounted on the crank pin 5 within the combustion chamber a as shown inFIG. 1. The structure of the bearing boss 7, peripheral wall 10, brim 11and corner openings 13 and 14 are the same as in the embodiment of FIGS.1, 2 and 3. Guides 9a are also similar to the guides 9 of FIGS. 1through 3 in that they extend radially outwardly from the bearing boss 7to the peripheral wall 10 and are disposed obliquely laterally atproperly spaced intervals around the outer peripheral face of the boss7. But they differ from the guides 9 in that each of the guides 9a hasthe radial outer portion 23 twisted with respect to its radial innerportion 24 as in a propeller blade According to this modification thecooling fluid supplied to the fluid chamber 12 is further activated toproduce a vortical current by the effect of the twisted curvature of theguide face and which twisted curvature gives the fluid flowing in theexhausting direction a rotational component about the direction of flow.Thereby the circulation of the cooling fluid through the chamber 12 isfurther facilitated and the partial stagnation of the fluid at thecorner of each chamber 12 is avoided.

FIG. 5 shows a further modified form of the rotary piston 6b which isthe same as shown in FIGS. 1 through 6 except for guides 9b. The guides9b are similar to the guides 9a of FIGS. 4 and 6 in that they extendradially outwardly from the bearing boss 7 to the peripheral wall 19 andare disposed obliquely laterally at properly spaced intervals around theperipheral face of the boss 7 and also have the radially outer portion23 twisted with respect to the radially inner portion 24. But they aredifferent from the guides 9a of FIGS. 4 and 6 in that the guides 9b areinclined in a counter rotational direction of the piston in the form ofa backward curved vane. In this modification, when the rotationalvelocity of the piston decelerates, the fluid within each chamber 12 isaffected by the inertia and is guided along the back face of the guides911 without vertical collision therewith because of backward inclinationof the guides. The fluid led along said backwardly inclined guide 9b isinevitably caused to flow laterally and radially inwardly when thedeceleration of the rotational velocity of the piston occurs, andthereby smooth exhausting of the fluid from the corner openings 14 andin a tangential direction with respect to the boss 7 is performed.

Due to the polygonal shape of the rotary piston and its eccentricrotational movement along the trochoidal curve of the inner face of thecenter casing, cooling fluid within each chamber 12 is affected by therespectively different rotational velocity of the chambers of the pistonand the centrifugal force caused thereby and the fluid flows in adifferent speed and direction within each chamber. In view of this factthe angle of inclination, twisting, etc. of the respective guides willdiffer so that the most effective fluid circulation condition in eachchamher is obtained. Also, in determining the said angle of inclination,twisting, etc. of the guides, viscosity, flow speed, spreading conditionof the cooling fluid within chambers and the number of fluid chambers,engine capacity, etc. will be taken into consideration.

The construction shown in FIGS. 7, 8 and 9 is another modification ofthe invention in which the structure of the annular center casing, endwalls, crankshaft, crank pin, rotary piston, internal and externalgears, etc. are the same as in the embodiment of FIGS. 1 through 6, butit differs from that shown in FIGS. 1 through 6 in the delivery and thecirculation system for the cooling fluid. That is, a crankshaft 3 isprovided with a longitudinal center bore 25 which is connected to asource of fluid (not shown). Formed within a crank pin 5c are branchedradial bores 26 commonly connected with the center bore 25 and extendingradially outwardly through a middle portion thereof. Fluid guides 90 arelikewise disposed between the bearing boss 7 and the peripheral wall asdescribed with respect to the embodiment shown in FIGS. 1 through 3, butthey are different from that of FIGS. 1 through 3 in that they areV-shape in cross section and are disposed so that each inclined blade 27is inclined respectively in the opposite direction from a center peak 28and laterally forwardly with respect to the rotational direction of thepiston 60. Extending radially through the bearing boss 7 and the bushing8 of the piston 6c are fluid ports 29 opening into each fluid chamber 12at a portion adjacent the center bottom corner of the V- shaped guides.Said fluid ports 29 are connected with the branched radial bores 26 sothat at a properly timed interval when the crank pin 5c rotates withrespect to the pitson 60 within the boss 7 during rotation of thepiston, the cooling fiuid is delivered through the ports 29 to eachfluid chamber 12 during the operation of the engine. At the oppositeends of the chamber 12 adjacent the bearing boss 7 are laterally openingcorner openings 13c and 140 which are the same as those shown in FIGS. 1through 6 but they are adapted, in this modified embodiment, forexhausting fluid from the chambers 12 in the opposite direction asdescribed later. Circular apertures c and 160, fluid holes 170 and 180are also adapted for exhausting the fluid.

According to this modification, cooling fluid is supplied in theconventional manner from the source of fluid (not shown) through thecenter bore 25 and fills the branched holes 26 and is permitted toradiate into each fluid chamber 12 as the holes 26 are connected withfluid ports 29 during rotation of the crank pin 5c with respect to therotary piston 60. piston 60 along the trochoidal face of the annularcasing 1 likewise causes the cooling fluid within each chamber 12 toflow in a vortical current in the rotational direction of the piston asshown by the arrows in FIG. 8, which is the same as described withrespect to FIGS. 1 through 6. In this modification, however, the fluidis divided at the center peak 28 when the deceleration of the rotationalvelocity of the piston takes place and is compelled to flow in theopposite directions along each inclined blade 27 towards the corneropenings 13c and 14c through which the fluid is simultaneously exhaustedin the laterally opposite directions to each circular aperture 150 and160. Exhausted fluid received within each aperture 150 and 16c isconveyed away through the fluid holes 170 and 180 provided in each endwall 2 and 2.

FIGS. 10 and 12 show a further modified form of a rotary piston 6d inwhich the structural elements are the same as in the embodiment of FIGS.7, 8 and 9 except for the fluid guides 9d. The guide 9d is diflerentfrom the guide 9c of FIGS. 79 in that each inclined blade 27d is at asteep angle of inclination at its radial innermost portion and the angleof inclination decreases as it extends radially outwardly, so that theexhausting fluid flowing along the blade 27d is caused to flow in aspiral and without resistance due to a vertical collision of the fluidagainst the guide face. The crankshaft and the crank pin having thecenter bore 25 and the radial bores 26 as shown in FIG. 7, can beadapted to support the modified piston 6d. The supply of cooling fluidis therefore through the center bore 25, radial bores 26 and the ports29 and, exhausting the fluid is, as described with respect of FIGS. 7-9,in the lateral opposite directions through the corner openings 13d and14d and conveying away of the fluid exhausted will be performed in thesame manner as recited with respect to the embodiment of FIGS. 7, 8 and9.

FIG. 11 shows another modified form of a rotary piston 6e in which thestructure is the same as that of the embodiments shown in FIGS. 7through 10 and 12. Guides 9e are also similar to guides d of FIGS. 10and 12 in that they are V-shape in cross section; each in- The eccentricrotation of the.

'clined blade 27e extends in the opposite direction from a center peak282 laterally forwardly with respect to the rotational direction of thepiston; each blade 27e has the angle of inclination decreased in theradially outwardly direction. But the guides 9e are different from theguides 9d or of FIGS. 8 through 10 and 12 in that the guides 9e areinclined in the counter rotational direction of the rotor in the form ofa backwardly curved vane. Ports 292 are also different from the ports 29of FIGS. 8 and 10 in that they are radially backwardly inclined withrespect to the rotational direction of the piston 6e. According to thismodification the backward inclination of the guides 92 and the ports 29cause flow of the cooling fluid into the chamber along the inclinedports 29s and guides 9e without vertical resistance due to the rotationof the piston. Also, when the rotational velocity of the pistondecelerates, the fluid within each chamber 12, due to its inertia, isguided along the back face of the said backwardly inclined guides,therefore, there is no confused currents in the exhausting fluid due tothe vertical collision of the fluid with the guide face. This modifiedpiston 6e is also supported by the crankshaft having the center bore 25and the radial bores 26 of FIG. 7 for supplying the cooling fluidtherethrough to the chambers 12 via ports 29s. Corner openings 13a and142 are adapted for exhausting the fluid in the opposite lateraldirections and such exhausted fluid is conveyed away in the same manneras described with respect to the embodiment of FIG. 7.

I claim:

1. A rotary internal combustion engine, comprising an annular casinghaving a trochoidal shaped internal peripheral wall, a crankshaftextending through said annular casing, a triangular rotary pistoneccentrically rotatably mounted on said crankshaft for rotation withinsaid casing and defining between said piston and said casing a chamberfor combustion of gases, said casing having intake and exhaust meansthrough which the gases to be combusted and the products of combustionare drawn in and exhausted, said triangular piston being hollow andhaving an internal wall forming a piston hearing boss supporting thepiston on the crankshaft, and having an exterior wall and lateral endwalls defining the hollow interior of the piston, cooling fluid vanesextending radially outwardly within the hollow interior of said pistonfrom the internal wall to the exterior wall and extending between thelateral end walls at an angle to a radial plane through the axis ofrotation of the piston, said lateral end walls having apertures thereinbetween said vanes for the passage of cooling fluid, and said annularcasing having lateral end walls with apertures therein opposed to theopenings in the lateral piston end walls for the passage of coolingfluid therethrough.

2. A rotary internal combustion engine as claimed in claim 1 in whichsaid vanes extend in the same direction all the way between said lateralend walls of said piston.

3. A rotary internal combustion engine as claimed in claim 2 in whichthe vanes are each twisted with the outer radial endof the vanes at agreater angle to said plane than the inner radial end.

4. A rotary internal combustion engine as claimed in claim 2 in whichthe vanes are inclined with the lateral edges at the outlet ends of thevanes leading the lateral edges at the inlet ends of the vanes withrespect to the direction of rotation of the piston.

5. A rotary internal combustion engine as claimed in claim 1 in whichsaid vanes have a V-shaped cross section with the apex of the V pointingin the direction opposite the rotation of the piston, and said pistonhaving cooling fluid inlet bores extending through the internal pistonwall and opening into the spaces between said V-shaped vanes within theinternal angles formed between the vane portions defining said V-shapedvanes.

6. A rotary internal combustion engine as claimed in claim 5 in whichthe vane portions at the apex of the V are inclined at an angle to atangent to the internal piston wall at the inner end of the vaneportions.

7. A rotary internal combustion engine as claimed in claim 6 in whichsaid inclination of the vane portions at the apex of the V is oppositeto the direction of rotation 5 of the piston.

Bentele 230-210 Bentele et a1 1238 Paschke 1238 Huber 1238 Paschke230145 Zimmermann 1238 DONLEY I. STOCKING, Primary Examiner.

W. I. GOODLIN, Assistant Examiner.

1. A ROTARY INTERNAL COMBUSTION ENGINE, COMPRISING AN ANNULAR CASINGHAVING A TROCHOIDAL SHAPED INTERNAL PERIPHERAL WALL, A CRANKSHAFTEXTENDING THROUGH SAID ANNULAR CASING, A TRIANGULAR ROTARY PISTONECCENTRICALLY ROTATABLY MOUNTED ON SAID CRANKSHAFT FOR ROTATION WITHINSAID CASING AND DEFINING BETWEEN SAID PISTON AND SAID CASING A CHAMBERFOR COMBUSTION OF GASES, SAID CASING HAVING INTAKE AND EXHAUST MEANSTHROUGH WHICH THE GASES TO BE COMBUSTED AND THE PRODUCTS OF COMBUSTIONARE DRAWN IN AND EXHAUSTED, SAID TRIANGULAR PISTON BEING HOLLOW ANDHAVING AN INTERNAL WALL FORMING A PISTON BEARING LOSS SUPPORTING THEPISTON ON THE CRANKSHAFT, AND HAVING AN EXTERIOR WALL AND LATERAL ENDWALLS DEFINING THE HOLLOW INTERIOR OF THE PISTON, COOLING FLUID VANESEXTENDING RADIALLY OUTWARDLY WITHIN THE HOLLOW INTERIOR OF SAID PISTONFROM THE INTERNAL WALL TO THE EXTERIOR WALL AND EXTENDING BETWEEN THELATERAL END WALLS AT AN ANGLE TO A RADIAL PLANE THROUGH THE AXIS OFROTATION OF THE PISTON, SAID LATERAL END WALLS HAVING APERTURES THEREINBETWEEN SAID VANES FOR THE PASSAGE OF COOLING FLUID, AND SAID ANNULARCASING HAVING LATERAL END WALLS WITH APERTURES THEREIN OPPOSED TO THEOPENINGS IN THE LATERAL PISTON END WALLS FOR THE PASSAGE OF COOLINGFLUID THERETHROUGH.